Soil sampling and soil testing is the mandatory practice every farmer should do in his or her farm because this tests the soil and gives you a better decision on what plants to plant in this soil. Every crop does in different soil PH and type soil.
These farming practices will help the farmer discover the exact amount of fertilizers and the types of fertilizers he should apply in his farm. They also help in identifying the exact amount of time plants can take to mature and the amount of water capacity the soil hold – the drainage of the soil.
What is soil sampling?
Soil sampling is randomly picking small amount of soil in different parts of the farm to ascertain the types of soil and the plants that can be planted in the area. Also done to test nutrients and potential hydrogen in the soil.
Soil sampling methods are as follows:
- Zigzag method
In zigzag method, the soil samples are collected in a manner that seems like a zigzag form.
- Transverse method
Soil sampling in this method is done diagonally in the farm after the corners of the field are determined. The procedure involves taking soil along the lines to the corners forming two transverse lines.
Soil sampling should not be done in these types of places:
- Long used dead furrows, furrows that are not in use.
- Long used manure heaps.
- Between many planted trees.
- Terrace stands.
- In swamps
Soil sampling procedures
Before doing soil sampling, consider the type of land, weather and seasons. These are the procedures:
Vegetation from the sampling spot is cleared under vertical cut and made to a depth of 20 to 30 centimeters from the cropland and 6 to 10 centimeters for pasture land.
A slice is taken from the vertical cut using a spade.
Put the content in a polythene clean bag.
The steps above are repeated in different parts of the field preferably 20 to 30 spots depending on the soil sampling method you are using.
The soil from all the spots is thoroughly dried, mixed and crusted.
The composite sample from the mixture is taken to the agricultural laboratory for testing
What is soil testing?
Is deeply analyzing the results from soil sampling to determine the ability the soil will supply nutrients in the farm. It indicates how much time and fertilizer a farmer should use in his farm for maximum production.
Soil testing involves testing the soil PH. Soil PH is the acidity and alkalinity that the soil contains. PH is measured in a scale of 1 to 10 where 1 is more acidic than 6, 7.0 is neutral and 10 is a strong base or 10 is highly alkaline.
Note that depending with the number on the PH scale it determines the availability or unavailability of certain nutrients in the soil, for example, phosphate nutrients to plants at a PH of 6.5 to 7.5, a PH lower than this make phosphorus unavailable and nutrients like potassium, zinc and manganese are less available at a PH of 9 and above.
The word PH stands for potential hydrogen, making soil PH testing the measurement of concentration of potential hydrogen ions in the soil. Soil alkalinity is caused hydroxyl ions while soil acidity is caused by hydrogen ions.
Importance of soil PH to crops in the farm
- Different species of crops react different to soil PH and some affected by low PH or high PH than other, for example, barley is affected by low PH while tea does well in low PH.
- Plants damaged by various soil pests such as nematodes are more serious in acidic soil than in neutral soil.
- Various elements accumulates the soil and there concentration may increase to toxic levels and hence impair a plant, it determines the presence and absence of nutrients.